# Thread: Setting the domain and range of a line

1. ## Setting the domain and range of a line

I am doing a math project when I am drawing with conics (and lines as well) to make a picture.

I have a question about setting the domain and range of a line segment.

Since the domain and range of a line are generally infinite, I cannot use that for my project, so I must specify an equation for the line I am drawing along with a domain and range to cut off part of that line so only what I want is left.

If I want a line that goes from points (-7, -14) to (-4, 14) what would be the domain and range of that line?

I know the equation would be y = -14 but I'm not sure about setting the domain and range for that.

Sorry if it's a simple problem!

Also please tell me WHY so I can do it for the rest of my problems.

THANKS!

2. Originally Posted by qcom
I am doing a math project when I am drawing with conics (and lines as well) to make a picture.

I have a question about setting the domain and range of a line segment.

Since the domain and range of a line are generally infinite, I cannot use that for my project, so I must specify an equation for the line I am drawing along with a domain and range to cut off part of that line so only what I want is left.

If I want a line that goes from points (-7, -14) to (-4, 14) what would be the domain and range of that line?

I know the equation would be y = -14 but I'm not sure about setting the domain and range for that.

Sorry if it's a simple problem!

Also please tell me WHY so I can do it for the rest of my problems.

THANKS!
Dear qcom,

I think your equation of the line is incorrect.

The correct line would be, $\displaystyle \frac{y-14}{x-(-4)}=\frac{14-(-14)}{-4-(-7)}$

$\displaystyle y=\frac{28}{3}x+\frac{154}{3}$

Now since you want it from (-7, -14) to (-4, 14),

Domain = [-7,-4]

Range = [-14,14]